The "safety" concern is pure BS. It's about three things: the money, the money, and the money.
Vail pays a fee to the Forest service to operate a concession on forest service land. This is public land - ours - and Vail resorts gets to use it in exchange for a fee. The concession service includes operating lift-served skiing and also includes offering ski instruction among other things. Presumably, the ski instruction concession includes an exclusivity clause, and Vail pays extra for that.
So, since Vail pays for an exclusive concession to provide ski instruction, they're within their rights to enforce it - anybody who tries to do ski instruction on that swath of forest service land is "poaching" Vail's contract. I'm OK with that so far.
My issue is whether it's in the public interest to grant an exclusive concession for instruction. Granted, it doesn't make much sense to grant non-exclusive contracts to the lifts, grooming, snowmaking, trail maintenance, etc. But for instruction, wouldn't allowing competition increase the quality? Or at least allow the better instructors to get paid for their work rather than having to live like a ski bum? I understand the forest service requiring some sort of license and registration for instructors, but what's the point in only allowing one concessionaire, other than creating a monopoly?
Instruction is a huge cash cow for the resorts (charge $100/hr, pay the instructor ten and pocket the 90%difference - cha-ching!) and to a certain degree instruction subsidizes the rest of the operation. I understand why Vail would want exclusivity, but I don't understand why the Forest srevice should give it to them. Hey, it's our land, Vail is just a tennant.